The present invention relates to a derivative of a 1,1-dicyclohexyl cycloalkane, which is a novel compound not known in the prior art, a method for the preparation of the compound and a traction-drive fluid containing the compound.
One of the important technological issues in the automobile industry is to develop a compact and light-weight traction-drive apparatus. Needless to say, a compact and light-weight traction-drive apparatus cannot be developed without a high-performance traction-drive fluid used therein. Accordingly, the requirements for the performance of traction-drive fluids are increasing in recent years to withstand the use under extremely severe conditions or, in particular, to exhibit high performance with stability in a wide temperature range from low temperatures to high temperatures. For example, traction-drive fluids are required to have a high traction coefficient in a temperature range from low to high temperatures, low viscosity, excellent oxidation resistance and the like among various kinds of other properties.
In the prior art, proposals have been made in Japanese Patent Publications 46-338 and 46-339 for the use of a variety of compounds as a constituent of a traction-drive fluid. None of the prior art traction-drive fluids, however, can fully satisfy the above mentioned requirements for the properties of a high-performance fluid. For example, compounds having a high traction coefficient at high temperature generally have a defect that the viscosity of the compound is unduly high at room temperature and is rapidly increased as the temperature is decreased resulting in poor flowability and a great energy loss by agitation and thus the efficiency of power transmission is lowered. On the other hand, a compound having a low viscosity at room temperature to exhibit a high efficiency of power transmission at low temperatures usually has an unduly low traction coefficient at high temperatures and the viscosity thereof at high temperatures is so low that drawbacks are sometimes caused in the lubrication of the traction-transmission apparatus filled therewith.